The examples are short although there are a lot of them to read all at once.
Read one example at a time, in order. Don't try to read them all at once.
TASK Comment on the discussion board on the relevance of one of the examples to your year 13 learning.
Section One
Patterns of Evolution.
These sites link to examples for each of the patterns of evolution which you are required to discuss. A wider knowledge of examples is always a good thing!
New Zealand parrots are an example of three species that have diverged. The Kea, Kaka and Kakapo have diverged and adapted to distinctly different habitats due to different selection pressures in those habitats.
The first video clip link shows the Kea's ability to solve problems. Finding food in their habitat is more difficult so in order to survive and reproduce successfully Kea need to be resourceful.
The second video clip shows the Kaka in its forest habitat,waiting to be fed. The forest is a much richer environment than the alpine habitat so Kaka have not traditionally had to work hard to find food.
The third video clip was a bit unpredictable for the wildlife photographer but does illustrate some of the problems of being a young male, ground living nocturnal parrot, the biggest parrot in the world, with not many other individuals around to breed with.
This link goes to a documentary clip on youtube that explains a great deal about the kakapo and its habitat, worth a listen. The accent makes it hard for the narrator to pronounce Maori words properly, I apologise if the pronunciation offends anyone. http://www.youtube.com/watch?v=RboaG1qB7Kw&feature=related
TASK go to the discussion board and discuss the mechanisms involved in the divergence of the three New Zealand parrots.
Using separation of species to show Divergence in Human ancestry. http://www.newscientist.com/article/dn11330-pubic-lice-leapt-from-gorillas-to-early-humans.html this article illustrate how the divergence of one species (lice) into two different species (of lice) can be used to track the divergence of apes and human ancestors. The image in the website shows the distinction clearly.
This is a radio broadcast about the NZ Wren,the Rifleman. It lasts 12 minutes but does have some info about how or why the species may have diverged. Maybe you could have it playing in the background while you are doing other work on the internet so you can listen while you work.
Section Two
Processes of Evolution
There are five key processes which interact to complete the act of evolution. Gene Flow and Speciation. Reproductive Isolation. Responding to Selection Pressures. Natural Selection or genetic drift. Mutation
Speciation -
the process of making a new species, but it is also important for species to stay as separate species by preventing speciation. Hank and Crash Course Biology does a great summary - stay awake, he talks fast and says a lot.
Cichlid speciation due to differences in Courtship behaviour.
These 600 species of fish are separated by sympatric speciation due to selection of mates based on behavioural differences. There are no geograhic barriers to reproduction between the species.
These two power points are cute but not too sure about some of the examples used to illustrate the differences, (only 1 minute long each) prezygotic barrierspostzygotic barriers
R I mechanisms are part of the processof speciation - they work to keep a species separate, they try to stop a species become less adapted through a watering down of their successful alleles. The RI mechanisms are important when it comes to a new species diverging as well. This video goes over the Basics of Reproductive Isolation.
Populations can respond to selection pressures in three ways, stabilising selection pressures cause the population to remain the same, directional selection pressures will favour some extreme phenotypes over the other, and disruptive selection pressures favour the two extremes against the middle, we use bell curves to draw these changes.
Everybody thinks they know this, but there is a lot to it. Darwin was pretty amazing because he thought of it by himself (well he was working with some other thinkers at the time -Maltheus for example). Can you work out the four ideas that Darwin had that control the direction that a species evolves in ? Use the following three links and see if they give you the clues you need.
http://blogs.discovermagazine.com/gnxp/2007/07/skin-color-vitamin-d-folate/
Quite a high level article for year 13 article (but not out of your range if you concentrate, people), worth reading. I like the way it recognises that protecting skin from cancer is not really a selection pressure because many people have reproduced before their cancer occurs,so some other selection must be happening.
DId you work out the four ideas Darwin had yet? They were like this:
1 Populations overproduce their offspring
2 Because of this overproduction there is competition for the resources the offspring will need to survive and reproduce.
3 There is variability in a population
4 The individuals that have the version that is most successful at getting the limited resources will survive and breed more.
Darwin did not have the assistance of knowing about genes like you do. He was working only on phenotype and you understand that the variation in phenotypes is due to genotypes and alleles.
Natural Selection is the mechanism for Populations to evolve.
The effect of the mechanism of Natural Selection on Evolution . Watch the Power Point.
The class of 2012 completed the student tasks stating why Darwin's observations were significant. On the discussion board, discuss how important the habitat of the population is to the process of natural selection.
Genetic Drift
Sometimes selection pressures and best suited doesn't mean you will survive to breed Sometimes there is just luck. This is how there is evolution which sometimes is NOT driven by natural selection, this is called Genetic Drift. There are examples of populations where the next generations alleles are a result of a Founder Effect or a Population Bottleneck. These populations are affected by the lucky ones survived to breed the next generation, not necessarily the best phenotypes.
I like this cute video, you could make one just like it. Pay attention to the lego character details.
Scientists disagree whether speciation is a slow gradual buildup off changes over time,as in the evolution of the Horse,or a rapid burst of changes when a group becomes reproductively isolated. One process is called Phyletic Gradualism,the other is Punctuated Equilibrium.
There are examples supporting both theories in nature.
This power Point clearly explains how punctuated equilibrium works.
When using diagrams to compare the theories,notice how in Punctuated Equilibrium the new species suddenly evolves, on the time scale there is a flat line between the two species, whereas in Gradualism the time scale has each species merging into a new species over time.
Be careful because these diagrams have time and evolutionary change on different axis!! Who does that!
Diagram illustrating the difference in phyletic gradualism versus punctuated equilibrium. In the phyletic gradualism model there is slow continuous morphologic (or other) change as one species evolves into another. In the punctuated equilibrium model, there are long periods of no or very little change (stasis) punctuated by rapid evolution of new species. The figure (caption mine) from: http://www.zoology.ubc.ca/~bio336/Bio336/Lectures/Lecture23/Overheads.html.
Use the Discussion board to explain what the habitat has to do with whether speciation will be by Gradualism or Punctuated Equilibrium. What evidence would scientists find to support that Gradualism had occurred?
http://statedclearly.com/videos/ This website promotes understanding of evolution, it has a series of animated videos on a range of topics, by now you are well informed enough to make the most of the information on their website.
Evolution Page
There is little argument now that Evolution by Natural Selection is fact.Darwin's Finches are an icon in Biology.
==
==
Build your Knowledge of classic examples.
The evolution gems pdf page illustrates some outstanding examples supporting Evolution.
Each example illustrates a key point.
The examples are short although there are a lot of them to read all at once.
Read one example at a time, in order. Don't try to read them all at once.
TASK Comment on the discussion board on the relevance of one of the examples to your year 13 learning.
Section One
Patterns of Evolution.
These sites link to examples for each of the patterns of evolution which you are required to discuss. A wider knowledge of examples is always a good thing!
Modern New Zealand examples, link to the University of
Waikato teaching site
http://sci.waikato.ac.nz/evolution/NZevidence.shtml
Coevolution.
http://biology.clc.uc.edu/courses/bio303/coevolution.htmhttp://answers.yahoo.com/question/index?qid=20090303175022AASCaHF (ask a question website,not always recommended!)
http://www.pbs.org/wgbh/evolution/survival/coral/index.html Predator and prey relationships
http://emedia.leeward.hawaii.edu/millen/bot130/learning_objectives/lo07/picturepage.7.01.html coevolution between pollinator honeycreepers with curved beaks that match their target flower.
http://evolution.berkeley.edu/evosite/evo101/IIIF1Casestudyofcoevo.shtml squirrels and pine cones, Berkeley University has some excellent resources, look around their website as well as using this case study.
Convergent Evolution.
http://animals.about.com/cs/mammals/a/aa061901a.htm for examples of evolution from Placental/ Marsupial Mammalshttp://www.biog1105-1106.org/demos/106/unit08/5a.convergentevol.html for Cornell University info on birds, cactus/euphorbia and streamlined animal examples.
http://videos.howstuffworks.com/discovery/30418-perfect-predators-mako-shark-speed-video.htm What are the similarities/differences between Mako and Tuna? This is a simple example.
Divergent Evolution
New Zealand parrots are an example of three species that have diverged. The Kea, Kaka and Kakapo have diverged and adapted to distinctly different habitats due to different selection pressures in those habitats.
The first video clip link shows the Kea's ability to solve problems. Finding food in their habitat is more difficult so in order to survive and reproduce successfully Kea need to be resourceful.
The second video clip shows the Kaka in its forest habitat,waiting to be fed. The forest is a much richer environment than the alpine habitat so Kaka have not traditionally had to work hard to find food.
The third video clip was a bit unpredictable for the wildlife photographer but does illustrate some of the problems of being a young male, ground living nocturnal parrot, the biggest parrot in the world, with not many other individuals around to breed with.
http://www.youtube.com/watch?v=NpF1HKsrA28
This link goes to a documentary clip on youtube that explains a great deal about the kakapo and its habitat, worth a listen. The accent makes it hard for the narrator to pronounce Maori words properly, I apologise if the pronunciation offends anyone.
http://www.youtube.com/watch?v=RboaG1qB7Kw&feature=related
TASK go to the discussion board and discuss the mechanisms involved in the divergence of the three New Zealand parrots.
A new Crab Species identified, example of divergent evolution.
http://www.underseahunter.com/n4/new-crab-species-discovered-at-cocos-island.html
Using separation of species to show Divergence in Human ancestry.
http://www.newscientist.com/article/dn11330-pubic-lice-leapt-from-gorillas-to-early-humans.html this article illustrate how the divergence of one species (lice) into two different species (of lice) can be used to track the divergence of apes and human ancestors. The image in the website shows the distinction clearly.
Adaptive Radiation
http://www.pbs.org/wgbh/evolution/library/01/6/l_016_02.html for Darwins Fincheshttp://tolweb.org/Heliconius/72231 for Adaptive Radiation in butterfly genus Heliconius
http://emedia.leeward.hawaii.edu/millen/bot130/learning_objectives/lo07/picturepage.7.01.html for examples of Honeycreepers.
http://pbskids.org/wildkratts/games/go-cheetah-go/ for a light break
This is a radio broadcast about the NZ Wren,the Rifleman. It lasts 12 minutes but does have some info about how or why the species may have diverged. Maybe you could have it playing in the background while you are doing other work on the internet so you can listen while you work.
Section Two
Processes of Evolution
There are five key processes which interact to complete the act of evolution.Gene Flow and Speciation.
Reproductive Isolation.
Responding to Selection Pressures.
Natural Selection or genetic drift.
Mutation
Speciation -
the process of making a new species, but it is also important for species to stay as separate species by preventing speciation. Hank and Crash Course Biology does a great summary - stay awake, he talks fast and says a lot.
Cichlid speciation due to differences in Courtship behaviour.
These 600 species of fish are separated by sympatric speciation due to selection of mates based on behavioural differences. There are no geograhic barriers to reproduction between the species.
http://www.tfhmagazine.com/details/articles/can-you-hear-me-now-sound-production-in-cichlid-courtship-and-speciation.htm
Reproductive Isolation
link to same examples as we described them in class, in case you need reminding.http://faculty.uca.edu/johnc/origin_of_species1441.htm
These two power points are cute but not too sure about some of the examples used to illustrate the differences, (only 1 minute long each)
prezygotic barriers postzygotic barriers
R I mechanisms are part of the processof speciation - they work to keep a species separate, they try to stop a species become less adapted through a watering down of their successful alleles. The RI mechanisms are important when it comes to a new species diverging as well. This video goes over the Basics of Reproductive Isolation.
Selection Pressures
http://tle.westone.wa.gov.au/content/file/c0a7f9da-2dc9-b549-578a-0f1a8921d148/1/bio_science_3b.zip/content/003_mechanisms/page_03.htm easy to read, simple text,don't do the activities,we have done better ones in class.Populations can respond to selection pressures in three ways, stabilising selection pressures cause the population to remain the same, directional selection pressures will favour some extreme phenotypes over the other, and disruptive selection pressures favour the two extremes against the middle, we use bell curves to draw these changes.
This website explains the bell curves. http://www.adonline.id.au/plantevol/natural-selection/
In the end, being a species is reinforced by many mechanisms, and speciation relies on a range of steps to happen to create a new species. This video illustrates the steps using Birds of Paradise species.
**The Process of Natural Selection**
Everybody thinks they know this, but there is a lot to it. Darwin was pretty amazing because he thought of it by himself (well he was working with some other thinkers at the time -Maltheus for example). Can you work out the four ideas that Darwin had that control the direction that a species evolves in ? Use the following three links and see if they give you the clues you need.
http://tle.westone.wa.gov.au/content/file/c0a7f9da-2dc9-b549-578a-0f1a8921d148/1/bio_science_3b.zip/content/003_mechanisms/page_02.htm
Simple text that introduces the deductions made based on Darwin's observations.
http://science.howstuffworks.com/environmental/life/evolution/natural-selection5.htm Case Studies in Natural Selection
http://blogs.discovermagazine.com/gnxp/2007/07/skin-color-vitamin-d-folate/
Quite a high level article for year 13 article (but not out of your range if you concentrate, people), worth reading. I like the way it recognises that protecting skin from cancer is not really a selection pressure because many people have reproduced before their cancer occurs,so some other selection must be happening.
DId you work out the four ideas Darwin had yet? They were like this:
1 Populations overproduce their offspring
2 Because of this overproduction there is competition for the resources the offspring will need to survive and reproduce.
3 There is variability in a population
4 The individuals that have the version that is most successful at getting the limited resources will survive and breed more.
Darwin did not have the assistance of knowing about genes like you do. He was working only on phenotype and you understand that the variation in phenotypes is due to genotypes and alleles.
Natural Selection is the mechanism for Populations to evolve.
The effect of the mechanism of Natural Selection on Evolution . Watch the Power Point.
There are lots of simulations, we like this one, Darwin's Game of Survival.
The class of 2012 completed the student tasks stating why Darwin's observations were significant. On the discussion board, discuss how important the habitat of the population is to the process of natural selection.
Genetic Drift
Sometimes selection pressures and best suited doesn't mean you will survive to breed Sometimes there is just luck. This is how there is evolution which sometimes is NOT driven by natural selection, this is called Genetic Drift. There are examples of populations where the next generations alleles are a result of a Founder Effect or a Population Bottleneck. These populations are affected by the lucky ones survived to breed the next generation, not necessarily the best phenotypes.I like this cute video, you could make one just like it. Pay attention to the lego character details.
http://www.youtube.com/watch?v=Q6JEA2olNts
lego simulation that explains the examples of Founder Effect, Bottlenecks and Genetic Drift really well
Mutation
Mutations are the original source of new alleles, without a mutation there won't be any variations for selection pressures to work on.Take a break Click to go to the evolution takeoff youtube version of Beatles Revolution, (light relief but the lyrics are pretty good)
(Level 2 Biology link back to the Genetics and Variation Page here.)
Section Three
Rates of Evolution
Scientists disagree whether speciation is a slow gradual buildup off changes over time,as in the evolution of the Horse,or a rapid burst of changes when a group becomes reproductively isolated. One process is called Phyletic Gradualism,the other is Punctuated Equilibrium.There are examples supporting both theories in nature.
http://science.howstuffworks.com/environmental/life/evolution/evolve-in-isolation2.htm Introducing the two theories.
When using diagrams to compare the theories,notice how in Punctuated Equilibrium the new species suddenly evolves, on the time scale there is a flat line between the two species, whereas in Gradualism the time scale has each species merging into a new species over time.
Be careful because these diagrams have time and evolutionary change on different axis!! Who does that!
Use the Discussion board to explain what the habitat has to do with whether speciation will be by Gradualism or Punctuated Equilibrium. What evidence would scientists find to support that Gradualism had occurred?
Section Four
General Information
http://www.pbs.org/wgbh/evolution/educators/teachstuds/svideos.html has great short videos to explain some concepts.
http://ngm.nationalgeographic.com/2009/02/darwin-legacy/ridley-text/1 National Geographic article that is easy to read and makes great sense. Provides an interesting link between Darwin and current Biotechnological applications.
https://www.youtube.com/watch?v=FHUlDQk8gL0 well presented common sense Myths Debunked.
http://statedclearly.com/videos/ This website promotes understanding of evolution, it has a series of animated videos on a range of topics, by now you are well informed enough to make the most of the information on their website.